Epitaxial Growth Loading Effect Reduction via Trench Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The epitaxial growth loading effect in semiconductor devices, such as 3D NAND flash memory devices, results in non-uniformity of epitaxial layer thickness due to differences in pattern density, leading to difficulties in device processing and potential performance issues.
Innovation Solution
A patterned device structure is created with a substrate, alternating insulating layers, and trenches of varying cross-sectional areas to form low and high pattern density regions, where the second insulating layer completely fills the first trench and remains open to the substrate, reducing the epitaxial growth loading effect by isolating the regions and allowing uniform epitaxial growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If simultaneous epitaxial growth is performed in low and high pattern density regions, then device fabrication efficiency is improved, but non-uniformity in epitaxial layer thickness occurs due to loading effect
Solution Approach 1:
The patent divides the substrate into separate processing zones by forming isolation structures (mandrels and insulating layers) between low and high pattern density regions. This segmentation allows each region to be processed independently, preventing the loading effect from causing thickness non-uniformity while maintaining the ability to perform epitaxial growth in both regions.
Solution Approach 2:
The patent introduces intermediate structures (isolation mandrels and insulating layers) that act as mediators between low and high pattern density regions. These intermediary elements physically separate the regions during epitaxial growth, preventing harmful interactions while allowing both regions to be processed simultaneously, thus resolving the contradiction between productivity and manufacturing precision.
2Manufacturing precision
If pattern density is reduced to minimize loading effect, then epitaxial layer uniformity is improved, but device scaling and integration density are limited
Solution Approach 1:
By segmenting the substrate into isolated regions using mandrels and insulating layers, the patent enables each region to be treated as an independent processing unit. This allows high pattern density regions (with small seed window areas) to be processed without being adversely affected by neighboring regions, thus maintaining both high integration density and uniform epitaxial growth.
Solution Approach 2:
The patent applies local quality by creating different structural conditions in different regions of the substrate. Isolation structures are selectively placed between regions to provide local separation, allowing each region to have optimized pattern density for its specific device requirements while maintaining overall uniformity across the entire substrate.
3Manufacturing precision
If isolation structures are added between different pattern density regions, then loading effect is reduced and epitaxial uniformity is improved, but device structure complexity increases
Solution Approach 1:
The patent uses intermediary isolation structures (mandrels and insulating layers) that, while adding structural elements, provide essential separation between regions. These intermediary components are strategically placed only where needed to prevent loading effects, balancing the increase in structural complexity with the significant improvement in epitaxial layer uniformity and device performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the epitaxial growth loading effect, ensuring uniformity in epitaxial layer thickness and improving device performance by controlling epitaxial growth rates across different pattern density regions, thereby enhancing processing and reducing current leakage.
Implementation Method 1
growing an epitaxial layer in the second trench
Data Source
AI summary
A method for reducing an epitaxial growth loading effect in a patterned device includes forming a first trench and a second trench in a substrate and in a first insulating layer over the substrate to form a low pattern density region and a high pattern density region. The first trench has a larger cross-sectional area than the second trench. The method further includes isolating the first trench from the second trench by using a first mask. The method further include disposing a second insulating layer in the first trench. The method further includes removing a portion of the first mask in order to expose the second trench. The method further includes growing an epitaxial layer in the second trench.